Method of synthesizing dyes and precursor compounds therefor
AssigneeEastman Kodak Company
InventorJohn David Mee
Life of this patent
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Abstract
A method of synthesizing a compound having a 1,3-thiazolidin-4-one ring appended at the 2-position by a double bond to the active methylene position of a ketomethylene or malononitrile moiety, which comprises reacting the corresponding ketomethylene compound or malononitrile with an isothiocyanate in the presence of a base, reacting the resulting product with a haloacetic acid or haloacetic ester, followed by eliminating water or alcohol to form the 1,3-thiazolidin-4-one ring. A fragment necessary to complete a merocyanine, oxonol, hemicyanine, benzylidene, cinnamylidene or holopolar cyanine dye can be appended to the 1,3-thiazolidin-4-one ring to obtain the desired dye.
Claims6
A method of synthesizing a compound having a 1,3-thiazolidin-4-one ring appended at the 2-position by a double bond to the active methylene position of a cyclic ketomethylene moiety, the method comprising reacting the corresponding cyclic ketomethylene compound with an isothiocyanate in the presence of a base, reacting the resulting product with a haloacetic acid or haloacetic ester, followed by eliminating water or alcohol to form the 1,3-thiazolidin-4-one ring.
A method of synthesizing a compound of formula (Ia):
- ##STR36## wherein R.sub.4 is an alkyl, aryl or heterocyclic group, and G represents a cyclic ketomethylene group as shown below:
- ##STR37## where * is the point of attachment of G to the ring shown in formula (Ia), and Z represents the atoms necessary to complete a substituted or unsubstituted 4 to 7 membered alicyclic or heterocyclic ring;
- the method comprising:
- reacting ##STR38## with an isothiocyanate of formula (II) in the presence of a base to obtain a compound of formula (III):
- ##STR39## where R.sub.4 is an alkyl, aryl or heterocyclic group;
- reacting compound (III) with a haloacetic ester or haloacetic acid of the formula XCH.sub.2 CO.sub.2 R.sub.6 to obtain a compound of formula (IV):
- ##STR40## and eliminating HOR.sub.6 to form compound (Ia);
- wherein X is a halogen and R.sub.6 is H, alkyl group or aryl group.
Dependencies are inferred from the claim text.